A Long Term Evolved (LTE) system supports Frequency Division Duplex (FDD) and Time Division Duplex (TDD). FIG. 1 shows the frame structure of a TDD system. In the TDD system, the length of each radio frame is 10 ms, and each radio frame is divided into two half frames with the length of 5 ms. Each half frame contains 8 time slots with the length of 0.5 ms and 3 special domains. The 3 special domains contain a Downlink Pilot Time Slot (DwPTS), a Guard Partition (GP) and an Uplink Pilot Time Slot (UpPTS), and the total length of the 3 special domains is 1 ms. Each sub-frame is composed of two continuous time slots, i.e., the kth sub-frame contains a time slot 2k and a time slot 2k+1. The TDD system supports 7 kinds of uplink and downlink configuration, as shown in Table 1. “D” in Table 1 indicates downlink sub-frames, “U” indicates uplink sub-frames, and S indicates special sub-frames containing the above 3 special domains.
TABLE 1configurationconversionserialpointsub-frame numbernumberperiod01234567890 5 msDSUUUDSUUU1 5 msDSUUDDSUUD2 5 msDSUDDDSUDD310 msDSUUUDDDDD410 msDSUUDDDDDD510 msDSUDDDDDDD610 msDSUUUDSUUD
Table 1 is uplink and downlink configuration of LTE TDD.
Theoretically, each cell may adopt TDD uplink and downlink configuration different from that adopted by adjacent cells to adapt diversification of services. Practically, if adjacent cells adopt different TDD uplink and downlink configuration, uplink transmission and downlink transmission of adjacent cells will be interfered with each other, which will be illustrated hereinafter referring to FIG. 2.
FIG. 2 is a schematic diagram illustrating interference between adjacent cells adopting different TDD uplink and downlink configuration in the prior art. In FIG. 2, a sub-frame 3 of macro eNB is an uplink sub-frame, and a sub-frame 3 of micro eNB is a downlink sub-frame. On one hand, the downlink data transmission of the micro eNB will interfere with uplink data which is transmitted by all terminals of the macro eNB to the macro eNB, and the closer the distance from the micro eNB to the macro eNB, the more serious the interference is; on the other hand, the uplink data which is transmitted by the terminals of the macro eNB will seriously interfere with downlink data transmitted by terminals of the micro eNB which is closer to the terminals of the macro eNB.
In order to avoid the interference between uplink transmission and downlink transmission of adjacent cells in the TDD system, the adjacent cells adopt the same TDD uplink and downlink configuration at present. However, uplink services and downlink services of different cells are unbalanced, i.e., a certain cell has more uplink services and adjacent cells of the cell have more downlink services. In this case, different cells need to adopt different TDD uplink and downlink configuration to meet respective service requirements. The above two kinds of requirements are inconsistent, and thus a problem to be solved by the present invention is to change current TDD uplink and downlink configuration without influencing the interference between adjacent cells, so as to meet the load requirements of diversified uplink and downlink services.